The Feel of Space

(left:eRiK, right:me)

That’s my friend eRiK. My mother emphatically titles him “eRiK the Dane.” eRiK and I studied Physics and Math together as undergraduates at The University of California at Berkeley. We share a great love of understanding, and whenever something’s puzzling me, from Set Theory to counting cards in BlackJack, I turn to him.

He’s been singing the praises of the show RadioLab on NPR lately and he was particularly stricken by a comment made by the well known Columbia University Physicist Brain Greene. Dr. Greene was discussing the expansion of the universe, and, this is hearsay now, he said that there is no center to the expansion. No origin, no point away from which things are expanding. This is, as eRiK said, unsettling. If you were blowing a bubble with chewing gum, bubble swelling from your mouth, the rate of expansion would be greatest at your lips where the mass of sticky stuff was being stretched into a sheet. If you were pulling a rubber band with your index fingers the rate of expansion would be highest near your digits and lower elsewhere. The point I’m trying to get across is that it’s difficult to think of examples of isotropic expansion of objects. This means spatially and directionally uniform expansion. A pizza pie made from a lump of dough is expanded into a sheet in a roughly constant spatial manner, but the spread is not directionally uniform, it is expanded radially, out from the center. Dr. Greene’s comment means that there is no direction or origin associated with the universes growth. As astrophysicists and astronomers watch stars getting farther away from eachother, it appears to be happening in the same way everywhere. At the very least this means that the universe itself must behave differently from every object in it.

There is one example that is a bit comforting : imagine that you lived on a line, confined to one dimension. Further, lets say this line was connected at the ends, an infinite hoop of 1D existence. If “something” caused this circle to grow radially out from the center (which wouldn’t be a part of the line itself of course), to those living on the line segment, it would appear as if everything was expanding isotropically. We could extend this idea to a 4 dimensional space-time as a hoop embedded in a higher dimensional space, but this is pure speculation.

This brings us to the topic that motivated the title of this post. What would it feel like to come to the edge of a universe? I don’t know that such a boundary exists or not, but we can certainly conceptualize a space like our own with well defined boundaries. This is not like being in a room with boundaries. The repulsive forces that we experience as a result of encountering walls are just that: fields of force. A boundary of space must be very different. There wouldn’t necessarily be any repulsive force, I imagine it more like asking a person to reach into the 14th dimension or backward in time. It doesn’t even make sense to try and conceptualize it. There is simply nothing to try or do or a direction to move in or a place to point to or anything. This is the closest thing I can imagine to arriving at a boundary to space. Not only would there be nothing there, our perceptual abilities would probably be quite stymied by such a thing. Again I have found myself in the slippery slope of speculation, and I invite others to weigh in on this. I’m not sure that anybody has the required personal experience to comment on this but I am sure that somebody could, in the great tradition of doing so in physics, suggest a thought experiment which would shed some light on the subject.

Saccade Gain Adaptation

(left:me right:Jordan)

I’m a graduate student. I study Neuroscience The City College of New York as a student of the CUNY Graduate Center. I work in the Biology Department of CCNY in the lab of Josh Wallman. I study a process known as Saccade Gain Adaptation.

Saccades (as I’ve described before in this very blog) are rapid point to point displacements of gaze. Unless you have a target which is moving that you can follow with your gaze, you make saccades. This is unique to eye movements. That is to say that there are no such constraints on arm or leg or any other kind of movements. If you want to move your arm from one location to the other, there are a tremendous number of paths to follow and speeds to employ. With eye movements, however, you have little to no control over the path taken or the speed of the action. If you’ve never heard of this, it’s useful to try and trace a line (like a corner where walls meet) slowly with your eyes. You’ll rapidly see that this is impossible, the best you can do is make small steps along the line. This is in contrast to say, holding out your hand and moving it across your field of vision while fixating on one of your finger-tips. In this case, you can make a smooth pursuit movement.

Saccade gain adaptation is a process through which the size of eye movements elicited by an abrupt change in position of a target is either increased or reduced. Below is a little flash movie that I made illustrating this procedure.

Why might the eye want to behave in this way? Let us suppose that over time the muscles in your eye become weak as a result of aging. It makes sense that the commands sent to your eye muscles must also change in order to accurately move your eyes to desired targets in the world. Josh (and I) think that this is not quite the whole story, but accept for the moment that it is possible and sensible for the brain to be able to change its saccadic gain.

Experimentally, we can induce gain adaptation in the following way: we start with “no step back” trials (runs) in which the subject fixate a small target. At some unpredictable (to the subject) time the target abruptly changes position, and the subject’s instructions are simply to follow the target. After some of these “baseline” trials, we move on to the “step back” trials. In this phase, the target steps to a new position, but when the subject moves their eye to the new target position, we move the target back slightly. Interestingly, if the step is small, the subject will not even notice the second target movement, they will simply follow it with their eyes. After many hundreds of trials (“Step Back (late)”), instead of making two saccades to reach the final position of the target (after its two steps), the subject will simply make one saccade to the final target location.

(Click on the black play button to see what a single trial looks like, and the trial type buttons to change the trial type)

In the above animation, there is a graph representing the type of data that we gather. We are only interested in the horizontal (or x) position of the gaze. All of the stimuli we’re using in the experiment are presented on a monitor. We use a computer to control the presentation of the stimuli, and we use a camera and a calibration procedure to record the direction of gaze from a subjects right eye. In the graph, the vertical axis represents horizontal displacement from some arbitrary zero point (I’ve purposefully ignored details such as this). So when the trace representing the target jumps up, that means it has moved to some new position to the right of where it formerly was. The same is true of the trace for the gaze position. When a trace steps down, it means the correspding thing (target or gze) has moved to the left. The set of gray dots merely represents the passage of time. I’m not sure if this description is complete enough, but hit the “play” button a bunch of times and puzzle over it if you’re still confused and it’ll make sense, or email me and I’ll explain ad nauseum.

A final note that there is a rather large (~%10 of the size of the eye movement) error in most saccades, I’ve simply idealized the graphics to simplify the presentation.

Mirror Neurons & Autism

The Mirror Neuron system (MNS) is thought to underlie imitation in primates, and has been implicated in Autism Spectrum disorder in humans(1, 2). First observed in Macaques, mirror neurons are classified as units that selectively increase their firing rate both during the execution of a motor action by an individual and while that individual observes the same action performed by another . The interest in the MNS in relation to autism was sparked by the fact that two of its major symptoms are generalized social interaction & communication deficits which would seem to rely on something like the MNS. In order to explore how MNS properties might differ in normal vs. autistic patients, Hugo Théoret has been performing experiments in human subjects. His results suggest that a general deficit of something akin to the mirror neuron system is present in autistic individuals.

(EMG stuff)

Dr. Théoret uses two techniques in his research on the mirror neuron system. These are electromyography (EMG) and transcranial magnetic stimulation (TCMS or TMS). EMG measures the voltage difference between ground and the skin nearby a muscle group. Muscle contraction is accompanied by currents which cause a change in voltage or potential. The is sensitive enough to detect voltage changes when an individual even considers a movement involving the measured muscle group. TMS is a coarse method of selectively activating cortical regions(3). The combined use of these tools has allowed Dr. Théoret to use simple experiments to draw interesting conclusions about individuals with Autism.

(TMS-er)

Dr. Théoret’s main finding can be summarized by describing two experimental outcomes. First, in normal (non-autistic) individuals, there is a reliable deflection of the electromyogram produced by having the subjects watch a video of an action being performed which involves the measured muscle. For instance, if the right bicep is being measured, there will be an observable deflection of the potential in that muscle when the subject watches a video of an arm lifting an apple. There is also a measurable potential-deflection in that muscle when the proper area of motor cortex is stimulated via TMS. Beyond these individual effects, there is a summation effect such that the deflection is even larger when the subject both observes the video and receives the TMS.

Second, in autistic subjects, there is no deflection of the electromyogram upon a subject’s observation of the above described video. There is in these subjects a potential produced by TMS of the appropriate area, implying that there is no defect in the circuitry to produce such sub-threshold muscle activation. Needless to say there is no summation effect in these subjects.

Dr. Théoret feels that this work implies that understanding of others’ actions is achieved by an individual mapping actions onto their own motor cortex(4). This is an intriguing hypothesis, but there are really two possibilities which both fit with the data. One is as suggested by Dr. Théoret, the other would be that the mirror neuron system alone interprets the intention of the action, and (when possible) maps the action onto the motor cortex. The former possibility would require, for instance, that anybody receiving sufficiently strong TMS would necessarily experience the feeling that they were either observing somebody perform an action or that they were performing the action themselves. This is in keeping with the theory will laid out by Daniel M. Wegner in his book The Illusion of Conscious Will. Without getting too far afield, Dr. Wegner believes that we have a general ability to ascribe agency to observed acts, attributing them to either to ourselves or to others.


The implications of this work are that a defect in the mirror neuron system is responsible for social-interaction pathology in patients with autism. In fact, some researchers believe that defects in the mirror neuron system could lead to all the deficits associated with autism(5). Of course, others feel that such dysfunction cannot be responsible for all the symptoms of autism(6). It remains to be seen whether any definitive explanation of the role of the mirror neuron system in autism will arise, but it is clear that it plays some role in the interpretation of actions.

References

1. Rizzolatti, G., & Craighero, L., (2004) The Mirror Neuron System, Annu. Rev. Neurosci. 27, 169-192.
2. Oberman, L.M., & Ramachandran, V.S., (2007) The simulating social mind: the role of the mirror neuron system and simulation in the social and communicative deficits of autism spectrum disorders. Psychol. Bull., 133, 310-327.
3. Fitzgerald, P.B., Fountain, S. & Daskalakis, Z.J. (2006). A comprehensive review of the effects of rTMS on motor cortical excitability and inhibition. Clinical Neurophysiology 117, 2584-2596
4. Théoret, H., Halligan, E., Kobayashi, M., Fregni, F., Tager-Flusberg, H. & Pascual-Leone, A. (2005) Impaired motor facilitation during action observation in individuals with autism spectrum disorder. Curr Biol. 2005 15, R84-R85.
5. Iacoboni, M., Dapretto, M. (2006) The mirror neuron system and the consequences of its dysfunction. Nat Rev Neurosci. 7, 942-951.
6. Hadjikhani, N., Joseph, R.M., Snyder, J. & Tager-Flusberg, H. (2006) Anatomical differences in the mirror neuron system and social cognition network in autism. Cereb. Cortex. 16, 1276-1282.

Miniature Eye Movements

Your brain doesn’t care about brightness, it likes contrast. In fact, by the time signals generated by light impinging on your retina propagate through its 10 layers of cells, brightness information has largely been discarded in favor of contrast, both spatial and temporal (see paragraph two for a description). A very simple example of this is demonstrated below. Initially the contrast (in time) of the two dots is the same because they are surrounded by the same brightness. When you click on the thin or thick surrounds button, the contrasts are now inverted between the two as evidenced by the change in percept. I guarantee that nothing about the dots themselves change, only the surrounding area.

(Shapiro, A. G., D’Antona, A. D., Charles, J. P., Belano, L. A., Smith, J. B., & Shear-Heyman, M. (2004). Induced contrast asynchronies. Journal of Vision, 4(6):5, 459-468, http://journalofvision.org/4/6/5/ica.html)

Now let me disambiguate a bit what is meant by temporal and spatial contrast. A painting, say Seurat’s Sunday Afternoon on the Island of La Grande Jatte, has plenty of spatial contrast, but because nothing changes in time, there is no temporal contrast. A movie screen filled with white which fades to black and back to white, oscillating, has plenty of temporal contrast and no spatial contrast. Now, if there is no temporal contrast at all in your visual field, the world will fade away. Your visual system needs temporal contrast. This is one of the purposes of so called fixational eye movements. These are small involuntary eye movements which you make between the large point to point movements called saccades that we use to change the direction of our gaze. So even if you were standing in front of a painting such that it filled your vision completely and only stared at one point, your eyes would move slightly, around your fixation target, to prevent the image from fading away. If somebody drugged your eye muscles so that there was no way to execute these small movements and filled your vision with an image that had no temporal contrast, the world would fade away.

The idea that brains only encode change and not static values of sensory data is pretty ubiquitous, and there are a wealth of examples. What I’d like to continue with, however, is another function of fixational eye movements that has been speculated about but only demonstrated of late. In a recent paper in Nature*, researchers have discovered that these small eye movements serve to enhance our fine scale spatial resolution. That is to say that without small eye movements, we are less able to detect the presence of and report the properties of fine spatial scale visual stimuli.

One very useful analogy is the way we run our fingers over something textured to better comprehend the shape of it. For example, suppose you were blindfolded and I put a piece of wood in your lap. I tell you that this piece of wood has some number of very small adjacent grooves cut into it at some particular position. If I asked you to find them and count them, I suspect that you would run your fingers across the wood until you found them and then rub your index finger over them a couple of times to determine the number. It seems a very natural way to do it, and this is exactly akin to making small eye movements to improve spatial resolution. Not making small eye movements like that would be akin to simply pressing your finger down straight on the grooves in an attempt to count them. Perhaps you could do alright at this if there were only one or two, or if they were very big, but as the task got more and more difficult you’d need to use the sliding technique in order to discriminate. The commonality here is that both your sense of touch and sense of sight are mediated by an array of detectors of fixed size and position, and some stimuli are simply too small and/or finely spaced to be accurately detected by the particular array of detectors you’ve got.

Here’s another example: suppose you were using a number of long same-diameter, same length rods to determine the topographical features of a small area of the bottom a pool of water. One way to do this would be to take many rods in a bundle and push them each down (still in a bundle) until they stopped, recording each of their heights individually. The problem with this method is that the resolution of your image of the bottom is limited to the diameter of the sticks. Assuming you can’t use ever thinner sticks (we can’t make the receptor size in our eyes or hands arbitrarily small), you can get a better resolution image by running a single rod (or many rods) over the area to be mapped, continuously recording the height. In this way you have more information than if you simply assign each rod to a single point on the bottom, increasing your resolution.

*Rucci, M., Iovin1, R., Poletti1, M. & Santini, F. Miniature eye movements enhance fine spatial detail Nature 447, 852-855 (14 June 2007)

Life


This is Carl Woese, he’s a biologist. Although I’ve been aware of several of the theories that he has espoused over the years, it wasn’t until recently that I attributed their authorship to this great thinker. Three of the “biggest” ideas that he’s responsible for are: the RNA world hypothesis, the current organization of the tree of life with three domains at the bottom, and the concept that there was a time, before species existed, when Darwinian evolution was not dominant because of the prevalence of horizontal gene transfer. Briefly, the RNA world hypothesis suggests that the most primitive version of life as we know it must have consisted entirely of RNA because RNA can act as both an enzyme (for which we mainly use proteins) and as an information storage molecule (for which we use DNA). The three domain system split the prokaryotes (simple cells having little to no internal membrane structure like bacteria) into two separate groups: bacteria & archaea. As to pre-Darwinian evolution and horizontal gene transfer, well the idea there is that before there were individual species, all the forms of life were so similar that there was massive intermixing of genetic information betwen living organisms such as we do with bits of electronic data today. This is incredible because it’s essentially akin to lizards appropriating wings from birds because they’re an effective way to avoid ground predators (excuse the hyperbole).

This is Gertrude (gerry) Brin and her grandson Colby, another great thinker. In reading Colby’s blog post from today, about his grandmother and life in general, I was reminded of what I think is Woese’s most powerful idea.

As an undergraduate student of Physics and Mathematics just starting to become interested in Neuroscience, and delighted by the fact that I could use my beloved equations to explain the behavior of biological systems, it none the less seemed to me that we would need an entirely new form of Mathematics, spurred by a paradigmatic shift in thinking, to really understand such complex systems as brains and indeed life in general. The best that I could do was to think of life as a temporary reduction in entropy. Perhaps you remember from some physics course that the universe is constantly tending towards an increasing state of disorder (entropy). This is true on a global (all-universe) scale, but smaller scale things such as life defy this. Life forms, temporarily, organize molecules. I’ve never been able to do much more with this idea, but I am fond of it and try to consider its ramifications once in a while.

One of the big problems we’ve had with understanding these very complex systems, is that all of our science has been reductionist for a very long time. We take something we don’t understand (a watch is one classic though not ideal example) and we open it up and look at all the pieces and how they fit and work together, and then we can understand in some way how the watch functions, but only in terms of the smaller pieces. I could say much much more about this, but I think Dr. Woese says it far better in the piece he wrote in Microbiology and Molecular Biology Reviews in 2004. I must also preface the following quote from that work by saying that I was turned on to ALL of this by Freeman Dyson’s fantastic article in the July 19th issue of the New York Review of Books (that link may expire fairly soon, I found it by googling the second paragraph of the text below), which also uses a substantial portion of the quote that follows.

“Let’s stop looking at the organism purely as a molecular machine. The machine metaphor certainly provides insights, but these come at the price of overlooking much of what biology is. Machines are not made of parts that continually turn over, renew. The organism is. Machines are stable and accurate because they are designed and built to be so. The stability of an organism lies in resilience, the homeostatic capacity to reestablish itself. While a machine is a mere collection of parts, some sort of “sense of the whole” inheres in the organism, a quality that becomes particularly apparent in phenomena such as regeneration in amphibians and certain invertebrates and in the homeorhesis exhibited by developing embryos.

If they are not machines, then what are organisms? A metaphor far more to my liking is this. Imagine a child playing in a woodland stream, poking a stick into an eddy in the flowing current, thereby disrupting it. But the eddy quickly reforms. The child disperses it again. Again it reforms, and the fascinating game goes on. There you have it! Organisms are resilient patterns in a turbulent flow—patterns in an energy flow. A simple flow metaphor, of course, fails to capture much of what the organism is. None of our representations of organism capture it in its entirety. But the flow metaphor does begin to show us the organism’s (and biology’s) essence. And it is becoming increasingly clear that to understand living systems in any deep sense, we must come to see them not materialistically, as machines, but as (stable) complex, dynamic organization.”

That last sentence just kills me, we must in some sense abandon our devotion to the material. For what is life about if not interaction.

Axo-Axo-Somatic Inhibition

Neurons communicate to eachother in the brain by chemical signals. They send out long ramifications called axons which synapse (connect) with other neurons (generally) on parts called dendritic trees. These connections are not physical in the sense that the cells do not share any inner-membrane space, but they do allow the communication of intercellular chemical signals with incredible speed. There is a small space called the synaptic cleft into which the signalling cell releases a chemical signal and at which the cell receiving the signal has receptors specific to that signal. Dendritic trees are places where signals from many other neurons are summed up, when a neuron recieves enough signals from those cells which synapse onto it, it fires an action potential at it’s soma or body. An action potential is a large transient increase in the voltage of the cell (don’t forget your brain is electric). That transient (called a spike) propagates down the axons of that cell much like an electrical signal does in a telephone wire or a television cable, to the synapses it forms with other cells and triggers the release of the chemical signals used to communicate. This is the story whether the signalling cell is telling it’s target to turn on (excitation) or turn off (inhibition). One difference is that excitatory signals generally go to the dendritic tree of another neuron while inhibitory connections can go to the dendrites or the soma (body). This is useful because the inhibition acts like opening a voltage drain and preventing the action potential from building up which (as I mentioned) it generally does at the soma. The specifics of the signalling molecules and receptors determines whether inhibition or excitation is being transmitted, and in general cells send either one or the other kind of signal. So if an excitatory cell wants to inhibit another excitatory cell, it must excite an inhibitory cell which in turn inhibits the target excitatory cell. When might the brain want to do that? Well lateral inhibition is a ubiquitous concept in brain circuitry. This is the idea that if I have a bunch of neurons all designed to report something appearing in different parts the visual field, it makes sense for them all to mutually inhibit eachother. Because the areas of the visual field to which single neurons respond overlap a bit, a line might excite a sort of fuzzy set of neurons in the cortex, if the ones that are responding most strongly inhibit the ones that are only responding weakly I can detect cleaner edges and have better spatial precision in general.

A new paper in Science presents evidence that inhibitory synapses can have another form1. In the image above you can see an illustration of each othese kinds of inhibitory synapses. Both the type I’ve already described (above) and the new kind (below). The difference is that in the new type, instead of having to send a signal to the inhibitory interneuron which in turn inhibits the target excitatory cell, the 1st excitatory can hijack the inhibitory synapse of the interneuron to rapidly and directly inhibit the target cell! Why is this so exciting? Well any time we can figure out something new about how that intricate mass of electrified flesh in our heads might accomplish some of the seemingly miraculous feats it does, I get excited. I take particular pleasure in understanding the mechanistic underpinnings of consciousness, and being a materialist (in the philosophical sense), I think that neuroscience is the way to do that. Beyond this, the specificity of this new mechanism is potentially greater than the earlier described variant. An inhibitory cell projects to many other excitatory cells so if an inhibitory cell gets turned on, it will turn off many other cells which may not be “what the 1st excitatory cell wants.” The other reason I’m excited by this is that I see it as a way to modify the receptive field properties of a cell while during processing rather than through some longer term “learning” or modification in general. Below is an illustration of the receptive field structure of a simple cell in the primary visual cortex.

These cells are the first place that visual information is represented in the visual cortex, and all visual percepts are built up from them. Consequently, it doesn’t make sense to change them over time too much. It’s like a computer monitor, pixels are a good universal way to represent many different types of images. You wouldn’t change the shape of pixels depending on the type of images you were going to see because we don’t have technology that could do it quickly and efficiently enough. Similarly, one keeps the receptive fields of cells in the primary visual cortex constant and then changes how that information is used at later stages. However, if there was some way to easily change the shape of pixels back and forth depending on the stimulus being displayed, it would be very useful. That’s one consequence of this, online modification of receptive field properties at a low level. We’ve got a lot to learn from the brain.

References

1. Ren, M., Yoshimura, Y., Takada, N., Horibe, S. & Komatsu, Y. (2007) Specialized Inhibitory Synaptic Actions Between Nearby Neocortical Pyramidal Neurons. Science 316, 758–761 (2007).

Memory

I was riding the NYC subway listening to my iPod the other day when it ran out of batteries (hard to relate to such an experience I know). I was a bit vexed because I had Massive Attack’s “Lately” stuck in my head and really wanted to scratch that itch. I realized that by focusing on the song, I was able to produce a damned good internal manifestation of it. I instantly tried specifically to do the same with a visual image, Max Ernst’s work (The Elephant Celebes, 1921) , but I could only remember object positions and placements; if I focused I could recall the pleasing quality of soft swaths of dark gray with silvery white punctuations that make up the central figure of the canvas, but never a detailed, full image. Perhaps some people can summon perfect pictures of a loved one’s face, but personally I’ve never been able to do that; only by relying on some other form of memory like a happy event am I able to better recall faces. I am explicitly, however, trying to avoid such considerations because this is one of the classic problems in confronting human memory, it’s capacity and quality are completely contingent on context. Despite all that is known and available to read on this subject, my inward exam led me to think about memories of unimodal (one sense at a time) sensory experiences in general.

I am really treading on thin philosophical and scientific ice by using introspection as my main mode of exploration, but this is meant to be neither of those things, merely thought provoking. Because this is such personal territory, it’s obvious that there will be some variation from person to person, for instance, in the extreme, a man blind from birth will find it decidedly impossible to recall any visual image, and can probably recall audio better than any person with sight. This person to person variation may have something to do with inherent differences in brain structure, including those completely lacking sensory apparati. So before I do a little run down of the various sensory systems, allow me a digression, starting from auditory stimuli, about brains that may facilitate the discussion to follow.

Music isn’t a very general example of an auditory stimulus, and this may have something to do with the fidelity of the remembered experience. There are a few factors which immediately come to mind that might be relevant: (1) the amount of cortex devoted to representing the type of stimulus in question, and (2) the involvement of mirror neurons, (3) the temporal quality of music. The Cerebral Cortex as it is “properly” referred to is the outermost few millimeters of the brain of higher organisms. The wrinkled quality that a brain has (if you’ve ever seen an image of one) is thought to be a way to increase the amount of cortex. This is where the brain does its most complex information processing. It is here that one can find single neurons (brain cells) which respond* to the various senses in such complex ways that single cells will react best when you are looking at a picture of Bill Clinton versus, say, a car or your grandmother. Mirror Neurons are wonderful little devices in your head which respond when you perform an action and when you observe another individual performing the same action. For example if you reach out and pick up an apple, the same mirror neuron will fire no matter how you do it. If you use a set of tongs for instance or daintily pick it up by the stem, and the same is true of the observed act, so that it seems mirror neurons encode intention of action. They’re very important for social interaction and learning and a host of other things, and they probably deserve their own post, but for now they are at the service of my argument about music and paintings.

The amount of cortex devoted to vision far outweighs any other sensory modality, certainly the visual cortex is larger than the primary auditory cortex. So it may simply be the case that it is more difficult for memories to light up all of the various parts of the visual cortex that are necessary to generate a truly accurate experience of sight.

When you hear somebody speak, mirror neurons potentiate, that is to say they make ready to use and facilitate the use of, the parts of your brain used for vocalising. This even goes so far as to provoke measurable electrical responses in the muscles of ones throat. When you watch somebody prick themselves it is thought that the mirror neuron system contributes to any sensation of pain or touch that you might experience as a result. It may thus be that when one is listening to music with singing, the mirror neuron system strengthens the auditory cortex’s memory based activity.

As to the temporal quality of music, this just doesn’t seem that relevant. I’m no more likely to be able to remember a series of images (unless it’s the final frames of Trufautt’s “The 400 Blows”) than I am to remember a single image.

Now, let’s see if these two ideas tell us anything when we try to examine other senses. Let’s consider the following 8 senses (What happened to five you ask? Well we need all these categories because the last three don’t really fit into the first five.). They are organized roughly by the amount of cortex devoted to them.

  1. Vision
  2. Somatosensation (touch)
  3. Audition
  4. Proprioception (muscle movement, posture)
  5. Gustation (taste)
  6. Olfaction (smell)
  7. Vestibular (balance, orientation)
  8. Interoception (hunger, thirst, drowsiness, air hunger, etc.)

This seems to immediately invalidate the suggestion that the amount of cortex devoted to a modality is what’s relevant. I have a very difficult if not impossible time remembering the experience of eating duck at WD-50, and yet the gustatory and olfactory cortical areas combined are smaller than the primary auditory cortex. As to the involvement of mirror neurons, it is incredibly difficult to asses. This is because one can’t really activate the mirror neuron system except by the use of vision or audition, so its potential utility in enhancing other unimodal memories is essentially nil. It might, however, facilitate the memory of a great LeBron James dunk or a beautiful Alvin Ailey dance piece. Despite this difficulty, it still seems to me that there is something extremely special about music. If I try to remember a series of isolated noises that I’ve heard it doesn’t even really make sense. I can think of specific sounds and noses: my fan blowing over my body on a hot summer night, a newer subway car’s increasing frequency whine as it picks up speed out of the station, a fluorescent bulb’s hum in the lab where I work. The problem with all of these is that I am unable to call these up without the associated visual experience as well, and then we’re back to the context/multi-modal issue. We must consider the possibility that our ability to both hear and make sounds facilitates a mirror neuron based enhancement of all music, vocal or otherwise; many instruments produce sounds well within the range of frequencies that we produce even if we can’t match their spectral qualities. I would really like to know if anybody out there feels that they have some sort of different experience of memory to the general one I’ve described here, or if they have theories of why we might perceive things in this way.

* I know respond is a weighted word, but I’ve got to cut this increasingly reductionist explanation off somewhere, if you’d like an explanation of what I mean by “respond” please email me and I’ll be happy to oblige.

Inception

Metempsychosis is a philosophical term from the Greek referring to transubstantiation: the changing of the substance of life from the material in to the spiritual, and vice-versa. I am named after James Joyce. For some, these two sentences might be enough to deduce the rest; before I BEGAN (not yet completed) reading Ulysses, I would have had no idea. Metempsychosis is pronounced by Molly Bloom as: “met him pike hoses,” which I simply delighted in. In the novel, the word stands for change (and Molly) in general. It is in opposition to Parallax which is a metaphor for constancy. As Ulysses is primarily a novel about human consciousness, for ME at least, both of these terms are about, respectively, the maliability and fixedness of conscious awareness (and indeed of all aspects of life). I wanted to choose one of these two, and I simply figured that the M-word-won-with-the-more-fun-pun.

Since I’m on the subject, I’ve been reading The New Bloomsday Book: A Guide Through Ulysses, by Harry Blamires. An excellent text for those of us who are not completely (but maybe partially) literature obsessed, and thus might need some help in understanding the very worth while details expounded in Ulysses. It gives reasonably simple explanations of each chapter in the book, touching on major themes and not getting too bogged down on any particular point. Specifically I turned to the capitulation of the “Scylla & Charybdis” (read: the 9th) chapter. I am not as familiar with Shakespeare as I’d like to be, and the chapter itself consists largely of Stephen Dedalus, and some other more ossified characters, discussing such matters in detail in a library. I must say I am really not sure of the validity of the literary claims made about Shakespeare here, but I found the result of the characters’ conversation stimulating. A point Steven makes that struck me with particular force was: the idea that life can only be understood post-hoc. This is specifically manifested in Stephen’s thesis that one can only understand the emotional effects of Shakespeare’s seduction at the hands of Anne Hathaway (she the older woman to his naive inexperience) by examining their reconciliation (in the form of his treatment of female characters in the later plays). I wasn’t even aware that Shakespeare’s plays had such an arc through them, that female leads and/or heroines change substantially over the course of his writings. I’m interested in validating that specific literary claim about Shakespeare with my arbiter: dad, but I really am entranced by the concept that emotional damage can only be understood through it’s reparation. This fits into the larger themes mentioned above: metempsychosis and parallax.

The metempsychotic change is Shakespeare’s shift: starting from a self influcted matrimonial alienation (spending most of his professional life living in London), and (again apparently) making his female leads into strong, somewhat conniving women such as in Hamlet, MacBeth, or the poem Venus and Adonis transforming into retiree gone back to wife at Stratford, and his representation of women differently in his later works (a suggested example here would be appreciated for reasons already alluded to). The very concept of reconciliation and being able to understand the changes that have occurred in one’s life requires that there is a continuous identity which we retain through of such life-events. Otherwise it would make no sense to consider the later Shakespeare related to the earlier. Thus the parallax, the parts of himself that are unchanging cast onto a background of shifting emotions. I often have this feeling of unreality, not understanding the experiences I am accruing until well after they have happened. This is nothing new of course, the thing I like about the example presented in Ulysses is that it is a general method for knowing when ones understanding will come, or at least knowing what is required to achieve such catharsis. I did not understand the relationship between my mind-body link and exercise/diet until I reformed the latter. I will not understand my seeming inability to have a long term relationship with a woman until I fall in love. Or to be less grandiose: I won’t be able to hit a really nice, lofty pitch shot until I do it right once and know what it feels like, I’ll always fall short to a scary looking gambit in a game of chess unless I win against it and see where the holes in it are.

My enthusiasm for this interpretation prompted me to re-analyse some other recent mental stimuli: (1) My pal Gideon Lewis-Kraus’ article in Harper’s about a small library in San Francisco, (2) John Updike’s piece in The New York Review of Books on Richard Serra’s show at MoMA. As this post is getting a little unwieldy, I’ll give you the briefly lensed version of each.

(Gid)

(1)

GLK’s piece is about a pair of librarians who want keep small personal libraries alive in the face of massive digital archives and private stacks. One strong motivation for this pair is to reform the way that information is arranged. They have their own idiosyncratic way of organizing the books into categories which is ostensibly to facilitate accidental discovery. What the article prompted for me was an understanding of the way the organization of data effects the structure of our thoughts. I had taken for granted that the way of cataloguing books in libraries was essentially a method to keep it’s effects on how we find our way through the information to a minimum. Clearly this is a bit naive. The path that we take from book to book, what passes through our hands on the way through, is the specific knowledge that we’re exposed to while looking for “what we need.” I think this is also a reflection of the general theme above in that in order to understand our own way of thinking, our own way of organizing our thoughts, exposing ourselves to other ways of doing so is paramount. This makes such libraries with adamant organizational purpose extremely valuable because they facilitate our understanding of the world and ourselves in a new way.

(One of Richard Serra’s myriad works)

(2)

The latter piece by Updike really frames Serra’s main theme nicely: to break down a viewer’s traditional “object hierarchies” or relationships to an object (specifically sculpture) through the manipulation of spatial relationships to the objects. If you’ve never seen Richard Serra’s work, click on that name, I cannot possibly hope to give a thorough enough description. The relationship to M(etempsychosis)&P(arallax) is that Serra challenges us to comprehend our understanding of those hierarchies, and of space in general, by providing us with a coherent means to interact with objects and experience space in nascent ways. It’s the same melody I’ve been whistling all day: by projecting ourselves against the scrim of his works, we are able to confront, and better understand by reconciling that clash, our individual assumptions about objects and form.